iOS 带有渐变色波纹动画

  最近有个朋友的项目里面做了波浪动画效果，刚好我的项目里也有这个需求，就把他的代码拿来改了，主要是实现了颜色渐变的效果。
  Github
  CocoaChina

  废话不多话，说一下实现过程：
  1、波纹动画主要依赖于CAShapeLayer的绘制，使用帧动画实现；需要使用多个CAShapeLayer通过y值变换组成（这里我只是用了2个CAShapeLayer）。
  2、渐变色由CAGradientLayer完成。

- (void)changeFirstWaveLayerPath {
    CGMutablePathRef path = CGPathCreateMutable();
    CGFloat y = _wavePointY;
    
    CGPathMoveToPoint(path, nil, 0, y);
    for (float x = 0.0f; x <= _waveWidth; x ++) {
        y = _waveAmplitude * 1.6 * sin((250 / _waveWidth) * (x * M_PI / 180) - _waveOffsetX * M_PI / 270) + _wavePointY;
        CGPathAddLineToPoint(path, nil, x, y);
    }
    
    CGPathAddLineToPoint(path, nil, _waveWidth, 0);
    CGPathAddLineToPoint(path, nil, 0, 0);
    CGPathCloseSubpath(path);
    
    _shapeLayer1.path = path;
    CGPathRelease(path);
}

- (void)changeSecondWaveLayerPath {
    CGMutablePathRef path = CGPathCreateMutable();
    CGFloat y = _wavePointY;
    CGPathMoveToPoint(path, nil, 0, y);
    for (float x = 0.0f; x <= _waveWidth; x ++) {
        
        y = _waveAmplitude * 1.6 * sin((250 / _waveWidth) * (x * M_PI / 180) - _waveOffsetX * M_PI / 180) + _wavePointY;
        CGPathAddLineToPoint(path, nil, x, y);
    }
    
    CGPathAddLineToPoint(path, nil, _waveWidth, 0);
    CGPathAddLineToPoint(path, nil, 0, 0);
    CGPathCloseSubpath(path);
    
    _shapeLayer2.path = path;
    
    CGPathRelease(path);
}

  调用：

_waveOffsetX += _waveSpeed;
[self changeFirstWaveLayerPath];
[self changeSecondWaveLayerPath];
   
[self.layer addSublayer:self.gradientLayer1];
self.gradientLayer1.mask = _shapeLayer1;
   
[self.layer addSublayer:self.gradientLayer2];
self.gradientLayer2.mask = _shapeLayer2;

  如果需要纯色背景的话 可以删除CAGradientLayer，给View和CAShapeLayer设置背景色；或者2个Color颜色值给相同的。